1. Field of the Disclosure
The present disclosure relates generally to a connective structure for a pin to planar substrate.
2. Prior Art
Presently, there is high demand for goods and products, such as implantable medical devices and electronics, wherein a small diameter pin or terminal needs to be joined with a thin plate. However, joining a thin plate to a small diameter pin is a delicate art, and to date there is no quick and efficient method to create a reliable joint between the two.
For example, a past attempt to join a pin to a substrate is shown in U.S. Pat. No. 6,032,359. In this patent, a laser is employed to cut a pattern of flaps in a substrate that is made of flexible polymeric dielectric film. The pin is then inserted through the substrate flaps in the location of the cut pattern. The resilience of the flaps holds the pin therebetween by simply gripping the pin. The pin may be readily removed from between the flaps, and when done, the flaps return to their initial position. However, this reference does not show a structure that permanently joins the pin to the substrate.
An example of joining a plate and shaft is U.S. Pat. No. 5,547,123, which shows a method of securing an apparatus part in a hole defined in a base metal plate. In this patent, a circular shaft is disposed in a hole defined in a base plate, and then the two are welded together by a laser that melts adjoining material portions of the base plate and the part. However, the bond formed between the base plate and part is not of optimum strength, as the laser welding consumes a portion of the base metal surrounding the hole. In other words, the base plate has a localized zone around the weld that is thinner than the surrounding base plate, and it is in this zone that potential stress fractures may develop.
In yet other attempts to hold a pin to a substrate, the pin is pushed through the substrate and joined thereto with an adhesive. Oftentimes, these adhesives are simply unable to withstand subsequent heating of the pin and substrate assembly, thus limiting the utility of this method of joining small diameter pins with thin plates.
Thus, there is a need for a joint that connects a small diameter pin with a thin plate, along with a methodology for making the joint. There is also a need for the completed joint to be sturdy and durable, yet still made in a quick efficient process.
The present pin to thin plate joint and method for making the joint provides for a new joint and a method for making a joint between a small diameter pin (terminal) and a thin plate (substrate). A superior joint is formed that is incredibly strong, yet still of the caliber that it may be made quickly, repeatedly, and efficiently. The assembled plate and pin may then be utilized in a flexible circuit.
The thin plate itself may define a first cutout, a second cutout, a third cutout, and a fourth cutout, that are arranged on the plate in an X-shaped pattern (X-shaped cutout). The thin plate further comprises an entry side and an exit side. The pin is alignable with the X-shaped cutout, and its contact end is movable through the plate from the entry side of the plate to the exit side. As this is done, a first tab member, a second tab member, a third tab member, and a fourth tab member are raised from the plate, such that the first tab member is adjacent to the second tab member, the second tab member is adjacent to the third tab member, the third tab member is adjacent to the fourth tab member, and the fourth tab member is adjacent to the first tab member. A rectangular opening is thus defined in the plate and flow spaces are defined between the sidewall of the pin and the tabs. Further, each of the tab members is triangular-shaped and each has a tip.
After the pin passes through the plate, the raised tab members are at substantially right angles with the exit side of the plate, each tab being bent at a bend. Also, the degree to which the pin passes through the plate is variable. That is, the pin is movable through the plate such that the contact end of the pin is: positionable between the exit side of the plate and the tips of the tabs, coplanar with the tips of the tabs, or extendable a distance away from the exit side of the plate (beyond the tabs).
A means for heating is employed to join the pin to plate, which may comprises laser welding. The laser beam generated by the laser is directed on the tabs and melts the tabs. The melt flows into the flow spaces defined between the rectangular opening and the pin. Upon cooling, a joint is formed between the pin and plate that is of high strength and capable of withstanding bending and torqueing without the pin and plate separating.
Thus, the present disclosure provides for a superior joint and method for making the joint between a small diameter pin and a thin plate.